1. Technical Field
The present invention relates to a test apparatus and a test method. In particular, the present invention relates to a test apparatus and a test method for testing characteristic of a device under test by changing a power supply voltage.
2. Related Art
Semiconductor devices having high withstand voltage (hereinafter high withstand voltage semiconductor devices) are known to be used for controlling motors of electric cars and for controlling alternate current fan motors, for example. In such a high withstand voltage semiconductor device, PN conjunction is separated by means of an insulating film of SiO2 for example, and so it is possible to incorporate circuits operating under low voltages and circuits operating under high voltages onto one chip.
Since insulating portions of high withstand voltage semiconductor devices contain capacitance, a defect may possibly occur attributable to a size of the gradient of the rising of a power supply voltage for example. In view of this, chances are that a defect may be detected when the gradient of the rising of the power supply voltage is larger than a predetermined value, while a defect may not be detected when the gradient is the predetermined value or smaller. Accordingly, a test apparatus is desired which is able to detect a defect attributable to a size of a gradient of the rising of a power supply voltage.
However, when testing a high withstand voltage semiconductor device, it is hard for a test apparatus to control the gradient of the rising of a power supply voltage to be supplied because the power supply voltage to be supplied is high.